[Volumetric examination of senile brain involution in dogs]

A heterogeneous population of 100 dogs was examined for age-associated brain involution. The dogs originated from the autopsy material of the institute and were selected irrespective of age, breed and sex. They had no history of neurologic disorders and exhibited no macroscopic cerebral lesions. After decapitation at the atlanto-occipital joint, the head was sawn through the median plane. The brain was removed and the skull reconstructed. The volume of the brain was measured by water displacement; the volume of the cranial cavity was determined by filling up with lead shot and pouring it into a measuring glass. In order to determine cerebral atrophy, the brain volumes were compared with the cranial-cavity volumes. The mean relative brain volume (mean brain volume divided by mean cranial cavity volume) for the 100 dogs was 88.7%. Connected with periods of life, the mean relative brain volumes slightly increased during the first 8 years and slightly decreased during the following years. With regard to the age groups 0-5 years, 5-10 years and more than 10 years, the average relative brain volumes were 88.4, 89.3 and 88.3%. These values did not show statistical significance, i.e. there was no evidence of a decline in brain volume in the ageing dog.